Thirteen years ago, many working-class women with a couple of children, a husband in a poorly paid full-time job, and a need to earn some extra money were wooed and won over by New Labour. During Blair's reign, their bounty included a minimum wage, a national childcare strategy and better parental and part-time workers' rights. Now we're heading for another election, why are those same working-class women deserting Labour in droves?

The sociologist Geoff Dench, in a Centre for Policy Studies report published next week, believes he has the answer. Working-class woman have deserted Labourbecause their views, as mothers who "prioritise family life", have been marginalised by a sisterhood of sharp-suited middle-class career women, whose outlook can apparently best be summed up in two words: Harriet Harman.

Anyone who lobs a stink bomb at the sisterhood has a certain audience on side immediately. However, when you look at Dench's argument, drawing on statistics from the British Social Attitudes study, an alternative interpretation is that it's not gender but class that's at issue – and money, or rather the lack of it, not middle-class madams that might be causing many women to walk away from the charms of Gordon Brown.

Dench argues that over the past 20 years there has been a steady growth in the proportion of people who support no political party. Among men, the rate of support for "no party" has nearly doubled from 8% in 1986 to 15% in 2006 . (They have presumably been betrayed by the brotherhood). Among women who describe their occupation as looking after the home, the proportion describing themselves as "no party" has tripled from 8% in 1986 to 24% in 2006. Among working-age single mothers, the increase for the same period has been from 7% to 25%.

In 1986, 52% of working age working-class housewives said they supported Labour. This support had dropped to 27% in 2008. And they haven't drifted to the Tories. Dench then leaps to the following conclusion:

"Women who value home and family life are becoming disenfranchised. The feminist 'sisterhood' has clearly failed them, and the result is that they are withdrawing their support from the mainstream parties. Politicians of all parties should be concerned about this... because… the proportion of young women who prioritise home and family has been growing steadily in recent years, and so their votes matter."

Home and hearth and women in pinnies gently rocking the cradle with one hand while they stir the pot with the other while their man does the "real" work in the outside world is an image that has long fuelled nationalist propaganda – as has a particular choice of language. Take, for instance, Dench's "disenfranchised". We are living in the age of the consumer and politics isn't immune. Describing oneself as "no party" does not necessarily mean disenfranchisement – the deprivation of choice – on the contrary, it could be read as a signal that choice rules supreme. These voters intend to "shop around".

"No party" could also mean that no party conveys the values, goals and vision of a society in which these voters can believe. This isn't about the sisterhood. It's about neglect of the white working class and the death of a clear Labour ideology. Or, to put it another way, perhaps some of those 52% of working class women who voted for Labour during a bad case of the blues under Margaret Thatcher now believe the party has become too posh for its own good – reflected in a House of Commons stuffed with white male bankers, lecturers and management consultants.

In this scenario, the small band of Labour women, including Harman, who could have done more have at least done something, including achieving a reduction in child poverty, changes to women's pensions and improved rights for carers, all impacting on women who are full-time mothers (who have increasingly powerful voices via the classless Mumsnet, Netmums and the Women's Institute).

Dench's arguments patronise women at home, insult women in paid work and do no service to men. Once there is equality in earning power, more men can opt out of the straitjacket of being the main breadwinner and play a greater role in care. Once care is given its proper value, inside and outside the home (and research tells us that more involved the dad, the better the child), and paid work ceases to be the only coin with currency, the whole of society benefits.

A recent paper by the TUC gives a further set of reasons for working-class women's disillusionment with Labour – that underline that far from wishing to stay at home full time, many women are frustrated in their inability to get a secure full-time or part-time job – and once the cuts in the public sector hit home (the public sector accounts for 40% of all jobs held by women), the situation will get very much tougher.

The latest YouGov poll says that women are split 37% to 29% in favour of the Tories, and that's before Sam Cam, the Conservatives' secret weapon, and the classic working mother, has been fully launched. Labour's election strategy will apparently be underpinned by claims that "middle-class mainstream" mums will suffer most if the Tories win and launch spending cuts. That's how far the party has drifted from its roots. And ironically, what there is of the sisterhood in the House of Commons is probably trying to tell it so.